Fluid flow detector for a fire alarm system
First Claim
1. A sprinkler flow detector for providing an alarm signal when a predetermined condition of fluid flow exists in a sprinkler system which includes a system side containing a fluid under pressure, said system side having at least one outlet port for allowing fluid to escape from the system side and at least one inlet port for admitting fluid into the system side, said detector comprising:
- a pressure transducer in communication with said system side for providing a first electrical output signal from which pressure of the fluid in the system side can be determined, andan electrical signal processing circuit for receiving the first electrical output signal from the pressure transducer and for providing the alarm signal whenever the rate of change of the first electrical output signal has a predetermined polarity relative to a predetermined threshold level for a predetermined interval of time, said processing circuit including a band-pass amplifier for providing a second electrical output signal representative of the component of said first output signal within a predetermined frequency range, a threshold detector for producing a third electrical output signal when said second output signal has a predetermined polarity relative to a predetermined threshold level, and means responsive to said third output signal for producing the alarm signal when said third output signal has been produced for a predetermined interval of time.
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Accused Products
Abstract
A sprinkler flow detector which can detect and rapidly respond to the onset of water flow in a sprinkler system which results, for example, from the release of one or more sprinklers. The detector senses the pressure vs. time profile of the system or house side of the sprinkler system. An increase in pressure is accurately tracked without causing alarm. If, however, the pressure falls in excess of certain predetermined rates and amounts, and holds in the lower state for in excess of a second certain predetermined amount of time, the detector enters an alarm state. In a preferred embodiment the detector features a trouble state in which it responds to one of several monitored conditions, for example, a component failure in the detector electrical circuitry, excessive pressure in the sprinkler system, or dangerously low pressure in the sprinkler system.
55 Citations
18 Claims
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1. A sprinkler flow detector for providing an alarm signal when a predetermined condition of fluid flow exists in a sprinkler system which includes a system side containing a fluid under pressure, said system side having at least one outlet port for allowing fluid to escape from the system side and at least one inlet port for admitting fluid into the system side, said detector comprising:
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a pressure transducer in communication with said system side for providing a first electrical output signal from which pressure of the fluid in the system side can be determined, and an electrical signal processing circuit for receiving the first electrical output signal from the pressure transducer and for providing the alarm signal whenever the rate of change of the first electrical output signal has a predetermined polarity relative to a predetermined threshold level for a predetermined interval of time, said processing circuit including a band-pass amplifier for providing a second electrical output signal representative of the component of said first output signal within a predetermined frequency range, a threshold detector for producing a third electrical output signal when said second output signal has a predetermined polarity relative to a predetermined threshold level, and means responsive to said third output signal for producing the alarm signal when said third output signal has been produced for a predetermined interval of time. - View Dependent Claims (2, 3, 4, 5, 6)
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7. In a sprinkler system containing fluid under pressure and including at least one inlet port for admitting fluid into the system and at least one outlet port for allowing fluid to escape from the system, a flow detector for providing an alarm signal in response to the escape of fluid from one or more of the outlet ports comprising:
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a pressure transducer in communication with the system for providing a first electrical output signal proportional to the pressure of the fluid in the system; a band-pass amplifier for producing a second electrical output signal proportional to the level of the component of said first output signal within a predetermined frequency band; a first threshold detector for producing a third electrical output signal when said second output signal has a predetermined polarity relative to a predetermined threshold level; and means responsive to said third output signal for producing an alarm signal when said third output signal has been produced for a predetermined interval of time. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification